Air gap fitting for drainage systems



Nov. 24, 1964 A. J. SMITH 5 AIR GAP FITTING FOR DRAINAGE SYSTEMS Filed Jan. 22, 1962 I3 34 33 2a 3! l2 2O INVENTOR. ARTHUR J .SM/TH A TTO/P/VEV United States Patent AIR GA? FHTTING FOR DRAiNAGll SYSTEMS Arthur 5. Smith, 4937 Golf Road, San .l'ose, Qalif. Filed Jan. 22, 1962, Ser. No. 167,538 4 Claims. Cl. 137-215) The present invention relates in general to drainage systems, and more particularly to an air gap fitting for drainage systems.

An object of the present invention is to provide an air gap fitting that is installed with facility and ease of operation.

Another object of the present invention is to provide an air gap fitting which is freely removable to facilitate the cleaning of traps or the like in a drainage system.

Another object of the present invention is to provide an air gap fitting that is adaptable for connection with different size waste pipes.

Another object of the present invention is to provide an air gap fitting which is adaptable for seating in the hub of a soil pipe or in a hub connection for a soil pipe.

Another object of the present invention is to provide an air gap fitting that minimizes leakage through the air gap ports thereof.

Another object of the present invention is to provide an air gap fitting whereby condensation forming on the outer surface thereof is collected by a hub connection.

Another object of the present invention is to provide an air gap fitting wherein there is minimum adherence of waste on the inner walls thereof.

Another object of the present invention is to provide an air gap fitting that aitords improved protection against contamination and pollution.

Another object of the present invention is to provide an air gap fitting that prevents waste from backing up into food receptacles and the like.

Other objects will appear upon perusal of the detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded view of the air gap fitting of the present invention illustrated in conjunction with a soil pipe hub connection.

FIG. 2 is a vertical section view of the air gap fitting and soil pipe hub connection shown in FIG. 1 taken along the central axes thereof and illustrated in their installed arrangement in conjunction with a soil pipe and a waste pipe.

FIG. 3 is a horizontal sectional view taken along line\ 3-3 of FIG. 2.

Illustrated in FIGS. 1 and 2 is a soil pipe hub connection 10 that has internal threads 11 (FIG. 2) at the lower portion thereof for establishing a threaded connection with the upper portion of a soil pipe A of a drainage sys tem. The hub connection 19 may be integrally formed with the soil pipe A in which event the threads 11 may be obviated. Seated within the hub connection 16 is the lower portion of the air gap fitting 12 of the present invention which serves to minimize contaminaton, pollution and the backing up of waste to food receptacles and the like in the drainage system.

It is to be observed that the air gap fitting 12 is slipped into the hub connection 10 and is freely removable therefrom. Included as part of the upper portion of the air gap fitting 12 is a waste pipe bushing 13, which slips into an upper central opening for sea ing and is freely remov- 5 able therefrom. The bushing 13 receives the lower extremity of a waste pipe B and may be formed with a central opening of various diameters to accommodate different size waste pipes.

In the preferred embodiment,- the hub connection 16 7 comprises a cylindrical body 15 (FIGS. 1 and 2) with a central upper opening 16. Below the opening 15 is Biiifiififi' Patented Nov. 24, 1%64 formed an annularflange or shoulder 17 (FIG. 2) which projects toward the axis of the body 15 at a 45 degree angle. At the lower extremity of the body 15 below the shoulder 17 is formed a central opening 18 having the wall thereof formed with the internal threads 11. The upper portion of the pipe A is received by the opening 18 in engagement with the threads 11 for establishing a threaded connection between the hub connection 10 and I the soil pipe A.

The air gap fitting 12 comprises a cylindrical body 26 having an outside diameter of a predetermined dimension so as to slip snugly into the central opening 16 of the hub connection 10. As shown in FIG. 2, the lower portion of the body 20 is received by the opening 16 and has a beveled lower wa1l21 that seats onto the annular'shoulder 17 of the hub connection 10. The contour of the wall 21 conforms to the contour of the annular shoulder 17 and, thus, has a 45 degree bevel. In this manner, a smooth flow path is provided. An axial opening 22 is formed in the body 20 and has a diameter substantially the same as the internal diameter of the annular flange 17 and the soil pipe A so as to provide a smooth flow path for the waste without obstruction.

Formed in the body 20 of the air gap fitting 12 intermediate the ends thereof and communicating with the axial opening 22 are a plurality of axially disposed air gap ports 25 (FIGS. 1-3). In the preferred embodiment, the air gap ports 25 are substantially rectangular in confiuration and the center lines thereof are spaced apart. The walls surrounding the ports are beveled inwardly and downwardly to minimize the escape of condensation through the ports.

Communicating with the axial opening 22 of the body 20 is an axial opening 26 formed at the upper portion of the body 20 above the air gap openings 25. The opening 26 is of a lesser diameter than the opening 22. A cylindrical wall 27 of the body 20 surrounds the opening 26. Meeting the wall 27 at the uppermost portion thereof is an annular flange or shoulder 28. At the opposite extremity of the Wall 27 is a wall 29 having an annular configuration and disposed at a 45 angle relative to a horizontal plane. This arrangement permits an accurate vertical jet-like discharge of waste through the air gap fitting 12 without obstruction and with minimum adherence of Waste to the inner walls, thereby providing a smooth flow path for the waste through the fitting 12.

The waste pipe bushing 13 of the air gap fitting 12 comprises a cylindrical body 31 having an outside diameter of a predetermined dimension so as to slip snugly into the reduced diameter axial opening 26 of the body 20. As shown in FIGS. 1 and 2, a lower wall 32 of the body 31 is beveled at a 45 angle to minimize adherence of waste t( the inner walls. Projecting outwardly from the body 31 is an annular flange or rim 33 that seats on the shoulder 28 when the bushing 13 is fully received by the axial opening 26.

Formed in the bushing 13 is an axial opening 34 of a diameter to accommodate the waste pipe B. The diameter of the opening 34 can be varied at the time of construction of the bushing 13 so that waste pipes of different external diameters can be received by the opening 34 and slipped snugly thereinto.

In the installation of a drainage system employing the air gap fitting 12 of the present invention, the hub connection 1% is secured at its lower portion in threaded engagement with the upper portion of the soil pipe A. Thereupon, the lower portion of the air gap fitting 12 is slipped into the axial opening 16 of the hub connection 1%) until the beveled wall 21 of the air gap fitting 12 is seated on the annular shoulder 17 of the hub connection 11?. It is to be observed that the air gap openings 25 are disposed above the hub connection (FIG. 2) and the axial opening 22 of the air gap fitting 12 is in communication with the opening of the soil pipe A.

The bushing 13 is slipped into the axial opening 26 until the rim 38 thereofi'seats on the annular shoulder 28. It is to be noted that if only one size waste pipe is to be employed, then the bushing 13 could be eliminated and the. opening 26 couldbe formed of a diameter to accommodate the outside diameter of the waste pipe B. At this time, the; waste pipe B is slipped snugly into the axial opening 34'. of the bushing 13. Hence, the opening of the waste pipe B is in communication with the axial opening 22 of the air gap fitting 12.

In the operation of the installed drainage system, waste passes through the waste pipe B, through the air gap fitting 1 2 and into: the soil pipe A. Should the soil pipe A be clogged. so that waste therein does not advance but backs up, then. waste will back up into the axial opening 22 of the air gap fitting 12. However, the waste backed up into the air gap fitting 12 will escape from the central opening 22' through the air gap ports 25 to prevent Waste from backing up into the waste pipe B. Thus, contamination and pollution of food receptacles and the like connected: to the waste pipe B are avoided.

It is tobe understood that modifications and variations of the invention. disclosed herein may be resorted to without departing from the spirit of the invention and the scope of the appended: claims.

Having thus described my invention, what I claim as new and desire-to protect by Letters Patent is:

1. In a vertically disposed drainage system, a pipe with ahub, and an air gap fitting telescopically disposed withinthe. hub of said-pipe in close tolerance lit for establishing sealing engagement therebetween, said air gap fitting comprising a first inner cylindrical wall forming a first axial opening for establishing a flow path for waste therethrough, said first inner cylindrical wall being formed with air gap ports communicating. with said first axial opening, a second inner cylindrical wall disposed above said first inner cylindrical wall and forming a second axial opening, said second axial opening communicating with said first axial opening and having a diameter less than the diameter of said first axial opening, said second inner cylindrical wall' having a lower portion thereof projecting into said first axial opening for establishing a flow path for waste with said first axial opening, whereby waste dischargedthrough saidsecond axial. opening passes. through said first axial opening without escaping through said air gap ports, and a third wall interconnecting said first and second inner cylindrical Wall's, said third wall being disposed at an angle relative to said first and second inner cylindrical walls and being directed upwardly and outwardly to reduce the tendency of waste to adhere to the wall surfaces.

2. A vertically disposed drainage system as claimed in claim 1 wherein walls surrounding said air gap ports are directed inwardly and downwardly to reduce the escape of condensation from within said air gap fitting.

3. A vertically disposed drainage system as claimed in claim 1 in which an upper pipe is telescopically disposed within said second axial opening of said air gap fitting in close tolerance fit with said air gap fitting for establishing sealing engagement therebetween, said upper pipe being removably seated within said air gap fitting and said air gap fitting being removably seated Within said hub of said pipe.

4. A vertically disposed drainage system asclaimed in claim 1 in which said hub of said pipe being formed with an inner annular shoulder angularly disposed relative to an inner wall of said hub and directed inwardly therefrom, and said air gap fitting being. formed with an annular wall on the lower portion thereof for seating on said shoulder Within said hub of said pipe, said. annular wall or" said air gap fitting having a configuration conforming to the contour of said shoulder within said hub of said soil pipe for close tolerance fit to establish sealing engagement therebetween.

References Cited by the Examiner UNITED STATES PATENTS 728,734 5 /03 Lovely 137-416 942,547 12/09 Cosgrove 2855-9r 2,037,962 4/36 Brown 285-332 2,102,848. 12/37 Kocour 137- 217 2,155,520 5/39 Wolff 137-216 2,174,743 10/39 Groeniger 137--217 2,288,247 6/42 Kunstorfi 137583 2,448,271 8/48 McClintock 285-177 2,480,791 8/49 Valerius 285-177 2,595,705 5/52 Rosencrans 28-531 3,086,543 4/63 McAuley 1372'16 CARL W. TOMLIN, Primary Examiner. 

1. IN A VERTICALLY DISPOSED DRAINAGE SYSTEM, A PIPE WITH A HUB, AND AN AIR GAP FITTING TELESCOPICALLY DISPOSED WITHIN THE HUB OF SAID PIPE IN CLOSE TOLERANCE FIT FOR ESTABLISHING SEALING ENGAGEMENT THEREBETWEEN, SAID AIR GAP FITTING COMPRISING A FIRST INNER CYLINDRICAL WALL FORMING A FIRST AXIAL OPENING FOR ESTABLISHING A FLOW PATH FOR WASTE THERETHROUGH, SAID FIRST INNER CYLINDRICAL WALL BEING FORMED WITH AIR GAP PORTS COMMUNICATING WITH SAID FIRST AXIAL OPENING, A SECOND INNER CYLINDRICAL WALL DISPOSED ABOVE SAID FIRST INNER CYLINDRICAL WALL AND FORMING A SECOND AXIAL OPENING, SAID SECOND AXIAL OPENING COMMUNICATING WITH SAID FIRST AXIAL OPENING AND HAVING A DIAMETER LESS THAN THE DIAMETER OF SAID FIRST AXIAL OPENING, SAID SECOND INNER CYLINDRICAL WALL HAVING A LOWER PORTION THEREOF PROJECTING 